Update on recreational and shellfish ban at Monaco Peninsula following sewage leak
Posted by Nelson City Council on 22 December 2011
Daily monitoring in the area is continuing (see table below).
Residents are advised to continue to avoid recreational activities that involve any water contact around the Monaco Peninsula, until further notice. Nelson City Council also reinforces shellfish should not be collected from these areas at anytime.
On Friday 28 October, Council staff identified a leak on the existing pipe between Monaco and Bell Island, approximately 100m off the Monaco Peninsula. The situation is, while we have observed seepage the exact location, extent and nature is unknown. The leak is estimated to be around five cubic metres per day.
The Nelson Marlborough District Health Board Public Health Service (NMDHB) was notified and has been kept regularly informed and together we have agreed on imposing restrictions and installing warning signs.
Below are the enterococci bacteria results of water quality tests carried out at the Monaco boat ramp and Tahunanui Back Beach, since we became aware of the seepage on 28 October. These results will be published on the Council’s web site and updated daily as further results are received.
Daily results for Monaco Boat Ramp and Tahunanui Back Beach | Date | Monaco Boat Ramp
Enterococci MPN*/100ml | Tahunanui Back Beach
Enterococci MPN*/100ml |
|---|
| 22/12/2011 |
10 |
10 |
| 21/12/2011 |
10 |
10 |
| NOTE: there was no sampling done from 15/12/2011 to 20/12/2011 (heavy rain). |
| 14/12/2011 |
659 |
429 |
| 13/12/2011 |
10 |
10 |
| 12/12/2011 |
87 |
10 |
| 11/12/2011 |
20 |
42 |
| 10/12/2011 |
10 |
1700 |
| 09/12/2011 |
10 |
10 |
| 08/12/2011 |
75 |
64 |
| 07/12/2011 |
164 |
20 |
| 06/12/2011 |
87 |
20 |
| 05/12/2011 |
782 |
124 |
| 04//12/2011 |
306 |
10 |
| 03/12/2011 |
10 |
10 |
| 02/12/2011 |
10 |
10 |
| 01/12/2011 |
10 |
10 |
| 30/11/2011 |
10 |
10 |
| 29/11/2011 |
10 |
20 |
| 28/11/2011 |
10 |
42 |
| 27/11/2011 |
10 |
2000 |
| 26/11/2011 |
75 |
192 |
| 25/11/2011 |
75 |
271 |
| 24/11/2011 |
10 |
64 |
| 23/11/2011 |
20 |
10 |
| 22/11/2011 |
10 |
10 |
| 21/11/2011 |
137 |
64 |
| 20/11/2011 |
10 |
10 |
| 19/11/2011 |
10 |
10 |
| 18/11/2011 |
10 |
10 |
| 17/11/2011 |
10 |
31 |
| 16/11/2011 |
10 |
42 |
| 15/11/2011 |
10 |
53 |
| 14/11/2011 |
10 |
10 |
| 13/11/2011 |
10 |
624 |
| 12/11/2011 |
42 |
2000 |
| 11/11/2011 |
64 |
624 |
| 10/11/2011 |
10 |
10 |
| 09/11/2011 |
10 |
10 |
| 08/11/2011 |
10 |
10 |
| 07/11/2011 |
10 |
10 |
| 06/11/2011 |
10 |
10 |
| 05/11/2011 |
<10 |
10 |
| 04/11/2011 |
178 |
20 |
| 03/11/2011 |
192 |
124 |
| 02/11/2011 |
624 |
- |
| 01/11/2011 |
10 |
- |
| 31/10/2011 |
10 |
- |
| 30/10/2011 |
2000 |
- |
| 29/10/2011 |
782 |
- |
*Most probable number
Council appreciate that the potential health risks and the current restrictions are of concern and inconvenience to all users of the area and Monaco residents in particular. We want to assure you that we are doing all we can to resolve the situation as quickly and with the minimum risk to public health and the environment as possible. Delaying repair work until we can minimize the risks is deemed the best approach.
Important information on the strategy to deal with the leak
The proposed strategy to deal with the leak was decided on after consulting with the NMDHB Health Protection Officer, the Environmental Inspectors, specialist consultants and contractors.
Our primary responsibility is to protect the health of the public while we continue to try to formulate a strategy to fix the leak once found.
The investigation into the leak is further complicated by the fact that the leak is on a live rising main (i.e. the existing pipe is in use and flowing under pressure) and is located in a position where the repair is within the tidal zones. The potential risk for digging down, locating, investigating a remedial solution and repairing the pipe is extreme, especially if something goes wrong. The result would be the release of thousands of cubic metres of raw sewage into the Waimea Inlet. Clearly Council wants to avoid this.
Based on this extreme risk, the decision was made to delay remedial works until such time as the new duplicate pipeline has been installed, reducing the risk of a major sewage spill. The duplicate pipeline is due for completion by the end of November.
A planned approach to carry out repairs on the current pipeline could take between two and three weeks. This is dependent on tidal conditions and weather and potential resource consent conditions.
Results of testing in Waimea Estuary
In consultation with the NMDHB and also based on the suspected location and size of the leak, tidal patterns and local estuarine geology, as well as compliance with the MoH and Ministry for the Environment Microbiological Water Quality Guidelines for Marine and Freshwater Recreational Areas, the continued restriction of public access with ongoing monitoring, signage and media advice is deemed the best approach.
For further information please contact: Manager Utilities on +64 3 546 0293
